Max’s arrival prompted them to give back, too, when Zuckerberg and Chan created the Chan Zuckerberg Initiative and pledged to donate 99 percent of their Facebook shares toward the advancement of human potential.

“Your mother and I don’t yet have the words to describe the hope you give us for the future. Your new life is full of promise, and we hope you will be happy and healthy so you can explore it fully,” the couple wrote in an open letter to Max.

“You’ve already given us a reason to reflect on the world we hope you live in.”